People here, like the "expert" that Nick linked, seem unable to distinguish between WinXP SP3 which is a beta program that should not be available to general users, even if you ask for it, and Office SP3 which is (and has been since January 2007) available.

Most of the changes in Office SP3 will have already been installed in bits and pieces if you've kept up to date with Microsoft Update, and there should be no urgency about installing OFFICE SP3. It's essentially a "rollup" of prior patches, made available for those who haven't kept up, or for those who might need to reinstall Office (from old disks) and want to get it back to current.

It is critical that you note that there are TWO DIFFERENT VERSIONS of Office SP3 available. Original Office installation disks are REQUIRED to do a successful install.

A "short version" is available for those who have their disks, or for networked/administered systems where the administrator can do the necessary redirection to make original source files accessible to the program. If the "source files" are not accessible or are defective, the installation will fail and all the problems claimed could occur.

A "full version" is available for download for those who don't have access to the original Office installation files.

Relatively few problems have been reported by those who used the correct version of the SP3 download.

If a sysadmin requested you to install at the office, the Office SP3 file you were given probably was the short version, and the admin presumedly "wrote the script" for the installation to access the original installation files on an office server. If you took that version home and tried to use it on your own machine, you'd find it broken and you'd be pretty well F***D.

If you downloaded the correct version from Microsoft, you should get demands that you insert your system installation CD(s) for the short version, and installation would stop if you didn't come up with them. If you downloaded your own "full version," it should be able to install successfully without additional resources.

Since very nearly all the changes will already have been installed piecemeal, Microsoft Automatic Updates shouldn't be force-feeding Office SP3 to you. You'd have to go to them and ask for it, unless your Office is so far behind on patches that the "rollup" version is more appropriate than installing all the prior patches individually.

Or so it seems from Microsoft information available.

John